


Man's Best Friend (With Benefits)

by halcyon1993



Series: The Kinky Adventures of a Wolf and His Boy [42]
Category: Teen Wolf (TV)
Genre: Alternate Universe - Human, Anal Sex, Bestiality, Bottom Stiles Stilinski, Breeding, Cock Worship, Come Swallowing, Deepthroating, Fur Kink, Hairy Derek Hale, Knotting, Large Cock, M/M, Oral Sex, Plot What Plot/Porn Without Plot, Praise Kink, Rimming, Rough Sex, Scent Kink, Sloppy Makeouts, Spitroasting, The Author Regrets Nothing, Threesome - M/M/Other, Wet & Messy
Language: English
Status: Completed
Published: 2018-10-28
Updated: 2018-10-28
Packaged: 2019-08-09 02:45:00
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 6,227
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/16441517
Author URL: https://archiveofourown.org/users/halcyon1993/pseuds/halcyon1993
Summary: When Stiles sleeps over at his boyfriend Derek's house for the first time, he is shocked to find himself aroused when he sees what's between the hind legs of Derek's dog, a male husky named Prince. His boyfriend is a horrible enabler.





	Man's Best Friend (With Benefits)

**Author's Note:**

  * For [Darksterek](https://archiveofourown.org/users/Darksterek/gifts).



> As always with this series, don't judge me for the depravity I have written…
> 
> If the subject matter present in this PWP grosses you out, I suggest you don't read it. Any negative comments that aren't constructive criticism will be deleted. Everyone else, enjoy! :D

Stiles has been dating the gorgeous Derek Hale for a little while now and he still can't believe his luck. How did he manage to get someone like Derek to even look at him? _Him_ , a scrawny loser whose self-confidence is still in the gutter from his lack of a social life in high school. For the life of him, Stiles can't figure out the answer, but he's thankful for whatever head injury Derek clearly sustained before they met that made him think they go together.

As they arrive at Derek's house at the end of another date, Stiles follows his boyfriend up the path to the front door with butterflies proliferating in his stomach.

Tonight is the night.

Even though they've been together for just over a month now, they haven't done anything but dry-hump—Stiles hasn't even seen Derek without his pants on, but he's sure that's about to change. All throughout dinner, Derek had this gleam in his pretty eyes that could only mean sexytimes were happening when they got back to his place later. Again, Stiles can't comprehend why Derek was looking at him that way when all logic dictates that he is beneath Derek on the hotness scale, but he isn't one to look a gift horse in the mouth. He's gonna take Derek and never let him go, because there is no way he can do better. He doesn't think _anyone_ could do better than Derek.

When they enter the house, both men shed their jackets, and Stiles looks around in awe as Derek takes his hand and gives him a small tour.

Everything is so clean, modern and expensive-looking—Stiles thinks that just the stuff in the living room costs more than everything in his apartment. Derek walks him past the black leather sofa and the huge flatscreen that has prize placement in the middle of a dark-wood entertainment centre. He takes him into the kitchen, where the modern aesthetic continues. The floor tiles, walls and cabinets are all white, a colour that's contrasted elegantly by the onyx countertops. Stiles is so caught up admiring the place—what he wouldn't give for a kitchen as nice as this—that he nearly jumps out of his skin when something wet and cold bumps against the hand not held in Derek's.

He squeals and leaps sideways, bumping right into his boyfriend.

"Don't be scared," Derek reassures him—while smirking, the sexy bastard. "It's just Prince. You two haven't been introduced yet."

Taking a breath, Stiles looks down and instantly melts when he meets ice-blue eyes and soft-looking white-and-grey fur. He has always had a fondness for dogs, ever since the first time his dad took him to the sheriff's station and he met the K-9 unit there. During every subsequent visit until his dad retired last year, Stiles would seek out every dog in the building and shower them with attention. If he was allowed, of course. Fortunately for him, most of the deputies had a soft spot for him as the sheriff's kid, so he was allowed more often than not.

"Hey, Prince," he greets, bending down to pet the husky. He doesn't have to bend far.

Prince is intimidatingly large. Stiles notes as Derek joins him in petting the dog that Prince's head comes up past his owner's waist—and Derek isn't a small guy.

"I didn't think huskies got this big," Stiles comments, in awe.

Derek chuckles. "Well, now you know better."

"Guess so."

After giving Prince a bit more fuss, Derek takes him outside to do his business and then, when the dog is lapping happily from his water bowl, the heat returns to Derek's eyes. Stiles forgets all about Prince when his boyfriend leads him upstairs to the master bedroom. How could he not, with what he and Derek are finally about to do?

* * *

An hour later, Stiles lies on his side with Derek in Derek's king-size bed, the maroon sheets pulled up to their waists as his boyfriend spoons him and snores quietly into the short hairs on the back of his neck. Derek's arms are so comfortable around him and his ass aches pleasantly from being split open by the older man's big cock, and it's as he's getting close to joining Derek in slumber that Stiles is reminded of Prince. They hadn't closed the door properly on their way inside the bedroom because they were all over each other, and at some point while Derek was making love to him for the first time, Prince must have slipped inside and curled up in the huge dog bed in the corner of the room. He stares right into Stiles' eyes with far too much intelligence for a canine.

"You're being creepy, Prince," Stiles murmurs.

He's unable to look away, and it's the dog who breaks eye contact first in order to lick himself. Stiles tracks the movement of Prince's long tongue as he licks over his junk, and for some reason he still doesn't avert his gaze. It's not until Stiles feels his dick twitch that he realises what he has been doing for two full minutes. He has a mini freakout and turns over in Derek's arms, showing Prince his back and trying in vain to erase the sight of the husky's furry sheath and balls from his mind.

God, he's sick. Here he is, sated after amazing sex with his equally amazing boyfriend, and suddenly he's lusting after an animal.

Yup, he's definitely sick.

Stiles buries his face in Derek's chest and scrunches his eyes shut tight. Maybe if he ignores the throbbing between his legs, it'll go away.

* * *

It doesn't.

A week later, Stiles still hasn't been able to stop thinking about Prince. He should probably have been avoiding spending any more time at Derek's house, but that would also mean saying no to spending time with Derek himself, and Stiles couldn't make himself do that. So he has slept four nights out of seven in Derek's bed, with Prince either sleeping in his dog bed in the corner or, if his owner allows it, draped across both of their legs. The warm weight of him had almost been torturous, and even though Derek worked many orgasms out of him on all four of the nights he slept over, Stiles always went to sleep with a painful erection.

All of that leads him to where he is now, just starting out on a walk with both Derek and Prince. Derek has the leash in his right hand and his left arm linked through Stiles' right as they follow the dog, who seems to already know that they're going to the dog park nearby. Derek keeps trying to engage him in conversation about dinner plans and what movie they should watch while cuddled up on the sofa with some wine or beers, but Stiles can barely keep up because his focus is on Prince.

He can't look away from how the dog walks with his tail curled up high in the air like always, giving Stiles a good view of his little pink asshole and the big furry balls that sway back and forth with every movement of his hindquarters. Stiles is half-hard and close to drooling when Derek forces his attention away from Prince by bringing them all to a stop.

"Hey, you okay?" the bearded man asks him with a concerned frown.

Stiles blinks and feels his face heating up. The only thing that stops him from panicking is the certainty that Derek couldn't possibly have figured it out. "Uh…y-yeah, I'm good," he answers, his voice higher than usual. "Why?"

"You're just acting kinda distant today, I guess. Are you sure everything's fine?"

"Yeah, I promise."

Derek still doesn't look wholly convinced, but he drops it. "Okay."

When they start walking again, Stiles makes more of an effort to participate in the conversation so as to not arouse Derek's suspicions.

* * *

A few hours later, Stiles and Derek are pressed close together on the sofa, just as they'd discussed on their walk. Stiles has his head on Derek's broad chest, and Prince is flopped on his side in his dog beg in the corner of the living room, his tail and head hanging over opposite sides. After wondering if his boyfriend has a dog bed in every room of the house, Stiles spends half his time watching the movie playing on the flatscreen and the other half watching Prince, which he finds out doesn't escape Derek's notice when Derek whispers in his ear.

"You're not being as subtle as you think you are, y'know," the older man says.

Startling, Stiles sits up and gapes at his boyfriend. "What?"

Derek raises an eyebrow at him, the corners of his lips curled up. "With your ogling of Prince, I mean."

"You…y-you know?"

"Yup. Like I said, you're not subtle, especially when we were taking him for a walk earlier."

Leaping up from the sofa, Stiles backs away and apologises profusely. He promises that he'll leave if that's what Derek wants him to do, and he fears for one awful moment when Derek gets up and approaches him that he's about to get his teeth punched in.

He should have known better. Even if Derek were mad, he isn't really the violent type. And Stiles knows that his boyfriend _isn't_ mad when Derek spins him in a 180 so that he faces Prince in the dog bed and then wraps his arms around him from behind. Stiles' heart still pounds in his chest, but it begins to slow when he realises he can feel something hard pressing against his ass.

"Look at him," Derek murmurs, biting the lobe of Stiles' ear.

Stiles looks, hardly daring to believe that this is really happening. Did he trip when he was making his way around the coffee table and hit his head? Is he in a coma? That seems like a more believable explanation.

Derek chuckles. "This is happening, Stiles," he says, because apparently Stiles asked those questions aloud. "Do you want him?"

"I…"

As he runs his eyes up and down Prince's long body, he admits to himself that yes, he does. He wants Prince so badly, as wrong as it is.

"Tell me. Tell me and I might let him have you," Derek prompts.

"I…I want him."

"Yeah? What d'you wanna do with him?"

Stiles opens his mouth to speak again but finds that he can't get the words out anymore. Derek takes mercy on him.

"Want me to tell you what I wanna see you do?" the bearded man asks, rubbing a hand up and down Stiles' shirt-covered stomach.

Stiles nods.

"I wanna see you suck his big doggy cock. Share some doggy kisses. Maybe even eat him out if we clean him up a bit first. Does that sound good to you?"

Another nod, this one a bit more confident as Stiles begins to accept that, because of a coma or not, Derek is really on board with him getting it on with his husky. How is this his life?

Derek releases him then and takes a step back. "Go wait in the bedroom. Prince and I will be up soon."

Scurrying to obey before his boyfriend can change his mind, Stiles enters the master bedroom and paces back and forth next to the bed. It's not too late to back out. He's sure that if he told Derek he didn't want to go through with it, Derek wouldn't make him. They could pretend this part of their evening never happened and go on living normal lives. Stiles would never drag Derek down into his depravity, and he'd never truly sink into depravity himself. It would remain a fantasy that no one else would have to know about, something safe that he could picture in his head late at night and then feel guilty about after he's come all over himself.

But then the door opens and Derek steps into the room with Prince trotting at his heel, and Stiles doesn't have the will to call it off.

He's really doing this. He's really about to have sex with a _dog_.

Once Derek has shut the door behind himself and Prince, he walks up to Stiles and without a word strips him out of his clothes. He takes his own off too, and the erection that sticks out big and proud from the dark curls at the base is enough to finally convince Stiles entirely that Derek wants to see him get fucked by his dog just as much as Stiles wants it. While Derek stares at Stiles with lustful eyes and that smirk still on his lips, Stiles ducks his head and blushes furiously. Prince sits obediently just inside the door and cocks his head at them, probably wondering what his humans are up to.

"Prince," Derek calls eventually, not looking away from Stiles' face. "Come here, boy."

As the dog walks over to them, Derek puts his hands on Stiles' shoulders and pushes him down to kneel on the floor.

"Oh God…" Stiles says when he raises his head again and discovers that Prince is _right there_.

"Give him a kiss, baby," Derek says, walking behind him. "I think he deserves one, don't you? All day you've been around him and not shown him any affection. He's feeling left out."

Stiles moves forward and presses his lips to Prince's snout. The dog sits there and lets him, his tail wagging behind him.

"You can do better than that, can't you?"

Stiles turns to peer up at his boyfriend. "W-what?"

"Kiss him like you mean it, Stiles," Derek tells him. "You want him to know you love him, don't you?"

"Yeah…"

"Then I think you should kiss him how you would kiss me."

"You mean— with tongue?"

Derek nods. A bead of pre-come falls from the tip of his cock to soak into the carpet.

Stiles looks back at Prince and sees that the dog is now panting with his tongue hanging out the side of his maw. His breath puffs out over Stiles' face, smelling of dog food, but instead of making Stiles' stomach revolt, the smell is just another reminder of how taboo this is and only serves to turn him on. After inhaling shakily to prepare himself, Stiles reaches up, tangles his fingers gently in the fur on the side of Prince's neck and brings their faces closer. He kisses Prince's cold nose and then, when he feels Derek copy him by threading thick fingers through the hair on his head, Stiles gathers enough bravery to bring his tongue into play.

He flicks it into Prince's open mouth and is glad when the dog doesn't bite it off. On the contrary, Prince licks him back. Stiles is embarrassed by the moan that slips out the first time their tongues brush together. The rough texture of Prince's is alien to him, nothing like Derek's or any of the people he kissed before he met his current—and hopefully long-term—boyfriend. As he tilts his head to the side to get a better angle and licks further into Prince's mouth, he decides that he really likes the roughness.

"Good boy," Derek praises quietly.

Stiles doesn't know whether he's talking to him or Prince and doesn't care. The compliment lights him up inside anyway.

Soon, Stiles just leaves his mouth hanging open and lets Prince lick inside it. Slobber mixes with saliva and dribbles down his chin, but he doesn't bring things to a stop. He's still enjoying it, and when Derek walks around next to him to get a better view, he knows that his boyfriend is enjoying it too. Derek strokes himself slowly with the hand not still in Stiles' hair, his entire length shiny as he uses his own pre-come as lube. Stiles peers up at Derek's face and blushes again when the older man shoots him an almost animalistic grin, all teeth and hunger.

When he eventually stops 'kissing' Prince, Stiles wipes his face off on his forearm and awaits further instruction.

If possible, Derek's grin gets even bigger. He stops stroking himself, releases Stiles' hair, slips his fingers beneath Prince's collar and gets him to turn around. This means that Stiles is once again met with the sight of the dog's asshole and balls.

Unlike when Stiles had stared at it during their walk, the fur around Prince's entrance is slightly damp and the hole itself looks clean and perfectly pink. Derek really must have cleaned Prince up while he made Stiles wait in the bedroom. He thinks he can guess what his boyfriend is going to ask him to do next, and sure enough, from his new position kneeling in front of Prince to keep him calm, Derek tells him to worship Prince's little doggy asshole the same way he had worshipped Derek's just a few nights earlier.

"Really?" Stiles squeaks. Even though he protests, his cock remains hard and aching.

"Really," Derek confirms. "I want him to experience how good your tongue feels. Don't you wanna make your mate feel good?"

Stiles worries at his bottom lip. "My mate?"

"Yeah. That's what he is now," Derek tells him. "After he's done with you tonight, he's gonna be your mate. And do you know what you'll be to him?"

"N-no?"

"You'll be his bitch. He'll have you down on all fours for him whenever he wants you."

Stiles gasps. "Oh my God…this is so fucking dirty."

"And yet you love it, don't you?" Derek reminds him. "Just embrace it."

His boyfriend is a horrible enabler, that much is fast becoming clear to Stiles. He lowers his eyes back to Prince's asshole and licks his lips, half from nerves and half from an awful feeling of desire that sweeps through him. Derek is right. He does love it, and right now all he wants to do is shove his tongue inside Prince's hole and give him the rimming of a lifetime.

So that's what he does.

With only a little shame—and the shame only makes him more turned on, if he's honest with himself—Stiles is at first cautious as he licks over Prince's entrance. He expects to taste something bad, but Derek must have done a good job making sure the husky is clean back here because all Stiles tastes is soap and skin. The skin is a bit different from how Derek's ass had tasted, but it's no less good. Stiles swiftly gets over his initial hesitance and, just as Derek had told him to, he embraces what he's doing. He's already started, so…in for a penny, in for a pound, as the saying goes.

The first time Stiles wiggles his tongue against Prince's hole, wanting to get inside, the dog squirms to get away, probably not used to a human sticking their face there. But Derek strokes his back and with a sharp command gets Prince to stay still.

Stiles should probably feel bad about potentially making the dog do something he isn't that sure about—an animal can't really consent, after all—but by that point he's so into eating Prince out that he doesn't have the patience to contemplate morals and all that crap. His cock is so hard it's getting sore, and he's dripping pre-come all over the floor, but he doesn't stroke himself to get some much-needed relief. Instead, he tangles his fingers in the fur on Prince's hips and pushes his face even further into his ass. He feels a sense of satisfaction and joy when he finally manages to get his tongue past Prince's tight rim and taste his insides.

"You're enjoying that, aren't you?" Derek asks him.

Stiles, not wanting to stop for even a second, just moans loudly and slurps at Prince's asshole like a starving man.

"Yeah, I thought you would. I knew from the first time we met that you were secretly kinky as hell."

 _You're just as bad,_ Stiles thinks.

Over the next few minutes, Prince actually starts to get on board with being rimmed, stretching out his forelegs so that his haunches are raised like an offering. Eventually, though, Stiles has to come up for air. He inhales shakily, his face once again a mess of spit. The fur around Prince's asshole isn't just damp but is matted down now, and the hole itself is slightly stretched and glistens with more spit. Stiles thinks it's one of the hottest things he has ever seen, which…weird.

But whatever. He's done questioning this new, wrong kink of his, and it helps a great deal that Derek is just as enthusiastic about him and Prince fucking.

Speaking of…

"Roll over, boy," Derek says when he sees that Stiles is finished with Prince's hole.

Stiles leans back as the dog follows his master's command, rolling onto his back in the space between him and Derek. He lies there panting happily with his legs sticking up in the air and his tail squashed beneath his back, but Stiles doesn't spend long thinking about that. How can he, when right in front of him are Prince's balls and sheath? It would be impossible for him to look at anything else, especially because, under his gaze, the tapered tip of Prince's pinkish-red cock emerges from the sticky opening at the top of his sheath. Stiles is going to have that buried inside of his ass very soon, and he can't wait.

"You still wanna blow him?" Derek enquires, his tone almost casual as he scratches his short nails over Prince's exposed belly, giving him some fuss for being a good boy.

"Uh-huh."

"You've gotta get him more excited then, don't you?"

Stiles nods slowly and reaches out a hand to touch Prince's sheath. The dog lifts his head to look at him but doesn't seem to disapprove when his new human gently rubs him.

Stiles can feel Prince's cock encased inside the soft flesh. It's so strange, especially when his efforts prove effective and more of Prince's cock begins to slide out. Clear fluid spurts from the pointed tip, some of which hits Derek's hand and makes him smile approvingly at Stiles. It's probably not very healthy, but in that moment, Stiles believes he would do just about anything to keep Derek smiling at him like that.

He keeps at it, rubbing Prince's sheath until he detects something huge inside. He doesn't really know that much about canine anatomy, but he has read enough kinky werewolf fanfic in his day to know that what he feels is Prince's knot. It bulges the sheath obscenely before popping out of the opening. It's the size of a baseball, and Stiles is nervous again at the thought of that fitting inside of his body. He has never taken anything that big before, not even Derek's considerable eight-inch length, and the rest of Prince's cock isn't exactly small. If Stiles had to guess, he'd say that Prince is somewhere around nine inches long, which makes sense given that he's a big dog.

Every inch of smooth pink flesh is covered in red spiderweb veins, which Stiles finds fascinating. Without even thinking about it, he wraps his hand around the knot at the base and angles Prince's cock so that it's pointing straight up in the air. While part of him is still full of shame for it, Stiles thinks that Prince's cock is beautiful in its own way. After licking his lips again and sharing a significant glance with Derek in which the bearded man silently encourages him, Stiles opens his mouth wide and sucks in the first couple inches of Prince's cock.

The husky whines and his hips jerk wildly on the carpet, his instincts to breed likely kicking in from feeling wet heat around him. The thought of being bred up by Prince has Stiles' eyelids fluttering. He sinks further down on Prince's cock, until the tip hits the back of his throat, and then he keeps going. He has never had much of a gag reflex, so he has little trouble deep-throating his new canine lover. But even when Prince is firmly lodged in Stiles' throat, he opens his eyes and is stunned to see that there are still a few inches he can't take, not to mention the knot. His asshole clenches as he imagines every single inch stretching him wide, nearly being torn apart as Prince forces his knot inside and locks them together.

When a spurt of pre-come suddenly shoots from Prince's cock, Stiles pulls off sputtering, eyes watering. Derek asks if he's okay, but he just waves him off with his free hand.

Once he has recovered, he tries again, more prepared this time. He concentrates harder, the newness fading so that he can focus more on the details—how Prince feels on his tongue, the silken nature of his cock, so different from human skin; the taste of his thin pre-come, bitter and salty and again different.

But just because all of it differs doesn't mean it's any less good.

Bobbing his head up and down, Stiles loses himself in blowing Prince, devoting all of himself to the task. The whole time, Prince whines and bucks his hips to try to get deeper inside Stiles' throat, but Stiles keeps his hand wrapped around the knot to stop the dog from finding success. He doesn't want to injure himself and end up as another news story, like that guy who had to go to the hospital because he deep-throated a dick too hard. He would never explain an injury like that with the truth, but even saying he hurt himself on Derek's dick would be humiliating enough.

Speaking of Derek, Stiles looks at the man through his eyelashes and finds him watching him right back. He has likely been staring the entire time, and the emotion in his hazel eyes makes Stiles feel like he is the sexiest thing on the planet. When the noises Prince makes get particularly plaintive, Stiles doesn't have the heart to tease him any longer. He releases the husky's cock with a wet pop and, after catching his breath, he speaks to Derek.

"D'you think it's time?" he asks, his hand still squeezing Prince's knot.

"Do you want it to be?" Derek counters, ruffling the fur over his dog's barrel-like chest.

"I do."

Derek smirks. "Then we'd better get on with it, huh? Before Prince gets too frustrated with us."

A minute later, Stiles is on his hands and knees in the middle of the bedroom, facing away from the door. Derek kneels next to him and spreads his cheeks with his hands.

"Come here, Prince," he commands the dog. "Come get your bitch ready."

Stiles bows his head and a second later feels Prince nosing around his ass. The husky doesn't seem to know what to do at first, but Derek coaxes him along until that long tongue swipes out over Stiles' hole. Stiles gasps and then moans on the next lick. Like kissing, it's so different getting rimmed by a dog than by a human. Stiles loves it so much that he does what Prince had done earlier, lowering himself onto his elbows to put his ass in a better position to be feasted on. Derek huffs a short laugh next to him, but Stiles can't find it in himself to give a damn if Derek knows just how big of a slut he already is for his dog.

After a while, Stiles' hole is wet and relaxed enough that Prince's tongue actually slips inside. Stiles moans and arches his back for more, which Prince gives him. The husky makes a cute little growling sound as he forces more of his tongue into Stiles' willing body, repaying what the human had done to him minutes before. It feels so good that Stiles fears he might come prematurely, so he reaches beneath himself and squeezes the base of his cock to stave off his orgasm. He doesn't want to come until Prince is fucking him for real.

"I think both my boys are ready for the main event, huh?" Derek observes fondly. He runs his fingers through Stiles' hair.

"Please…want him," Stiles entreaties. As much as he loves being rimmed by Prince, his hole is still empty and needy.

"Shh, I've got you," Derek soothes, moving his hand from Stiles' hair to run it down his back instead. "Just gotta make sure Prince is prepped too, so he doesn't hurt you too much."

Turning his head, Stiles stares with half-lidded eyes as Derek stands up and walks over to his nightstand to retrieve the lube stored there. When he has it, Derek disappears again behind Stiles, and Stiles has to rely on his ears when Prince stops eating him out. He hears his boyfriend pop the cap off the lube and then absolutely obscene slick sounds as Derek slathers Prince's long doggy cock with the stuff. He whimpers pathetically as he imagines what that must look like, which inevitably leads to images flooding his brain of Prince having sex with Derek instead. Maybe Derek can be the one getting fucked next time, because Stiles _really_ wants to witness that, to see how Derek's wonderfully hairy hole looks all fucked out, dripping with copious amounts of watery dog come.

Stiles is sure it would be amazing.

"Alright, have at him, boy!" Derek cheers, giving Stiles' ass a spank.

Prince must have figured out what Stiles is supposed to be to him, because without any more prompting he leaps up on the human's back and thrusts away. Stiles winces as Prince's sharp claws dig into his sides and the dog's tapered dick misses its target and jabs his balls instead, but he grits his teeth and bears it like a good bitch should. It isn't his place to control how things go. Prince is in charge right now, and Stiles is nothing more than a hole for him to fuck and fill with his pups.

 _Jesus fucking Christ, that's way hotter than it has any right to be,_ Stiles thinks. It helps him deal with his discomfort.

"Let me help you, buddy," Derek says after a short while. He reaches between the husky and Stiles, grabs Prince's cock and aims the tip right at Stiles' hole.

Stiles' head snaps up with a cry when, on the next rapid thrust, Prince buries himself right to the knot inside of his ass. The pain zings up his spine. Just a bit of rimming wasn't enough to prepare him to take Prince's massive doggy cock, but it's too late to do anything about that now. He doesn't actually want to do anything about it either. It plays into the fantasy that he has no control, which turns the pain into pleasure. Prince also doesn't seem to care at all, just fucks Stiles so quickly that Stiles is sure the husky's cock is a blur as he plunges it repeatedly into his new bitch's hole.

"How's it feel?" Derek asks him, coming around to kneel in front of Stiles.

"Hurts…" Stiles manages to respond.

Derek frowns concernedly. "Want me to get him to stop?"

Stiles shakes his head vehemently. "D-don't you d-dare! S'good!"

His frown vanishing, Derek smirks. "Alright." He raises his gaze above Stiles' face to look at Prince. "He looks so happy."

"Y-yeah?"

"Yeah. He's got his tongue hanging out and everything. He's grinning like the cat who got the canary, which is a weird analogy for a dog, but whatever."

Stiles can't stop the embarrassing noises that spill from his mouth as Prince continues to fuck him hard. The softness of the fur on Prince's belly rubs over his back, sending shivers down his spine. The pain is also lessening as his hole gets used to the stretch, which causes Stiles to forget his place. He attempts to take part in the proceedings, even as Prince's brutal thrusts rock his entire body. He pushes back every time Prince thrusts forward, seeking to get that big doggy cock even deeper inside of his body. Prince doesn't like this, as evidenced by the threatening growl that Stiles can feel as well as hear, and by the way his forelegs tighten around Stiles' hips.

Prince's claws nick him in a couple places, but the pain only makes the pleasure more intense, and Stiles knows that, until they heal, the small cuts will serve as an excellent reminder that he took a dog's dick up his ass. Still, it's a lesson learned. He goes still again and lets Prince have his way with him, which meets with Prince's approval. The husky stops growling and fucks him impossibly faster, at a speed that only an animal could reach. It's like he's trying to knot his bitch before he can escape.

Through all of this, Stiles never loses his awareness of Derek. When the older man tugs on his hair, he lifts his head and spots his boyfriend's leaking cock right in front of his mouth. Even with Stiles' sex-fogged brain, it's obvious what Derek wants. He opens his mouth and his cries and high-pitched whimpers are stifled as Derek immediately gags him on his cock. Derek doesn't even have to really do anything. He keeps his hand on the top of Stiles' head and just kneels there as Prince's thrusts push their shared bitch onto Derek's dick, ending with Stiles' nose pressed into Derek's pubic bone, inhaling the masculine musk embedded in his coarse pubes.

In heaven, or as close to it as he believes it's possible to get while alive, Stiles closes his eyes and doesn't fight it as all thought leaves his mind. He can't think at all, can only feel and taste and smell.

His own erection smacks against his barely developed abs, sending pre-come flying all over the carpet beneath him. The fire that has been smouldering in his lower gut for a while now burns brighter as it just goes on and on and on, until, when he feels Prince's knot battering against his rim, he ruins the carpet even more with his orgasm. He comes buckets, or at least that's how it feels. Stiles has never had an orgasm like this before, so all-consuming that his arms give out and his face would collide with the floor if it weren't for Derek holding him up.

Awareness returns slowly as both Prince and Derek use his ass and mouth like sex toys, and then it returns all at once as, with one final thrust, Prince forces his knot past the resistance of Stiles' hole. Stiles howls with pain, which sets off Derek's orgasm. His mouth fills with bitter seed that he swallows automatically so that he doesn't choke on it, and then he is finally permitted to regain his breath as Derek backs away so that his softening cock slips out of Stiles' mouth.

Stiles' upper body collapses, his ass still raised for Prince but his face smushed into the soiled carpet. "I don't think I can move," he mumbles, his words slightly slurred as the husky fills him with watery come.

"You've gotta wait for his knot to go down anyway," Derek points out, petting both of his boys affectionately.

"Right…"

"Just relax, okay? I'm gonna get you some water."

Stiles blinks lazily. "Sure."

In a flash, Derek returns and helps Stiles up so that his head is resting in his lap instead of the floor. He holds a straw to Stiles' lips. "Drink."

Stiles makes a small noise of pleasure as the cool liquid goes down his sore throat. It makes for an interesting contrast against Prince's warm come.

When Stiles has finished drinking, Derek sets the glass next to him. "So how was it?" he asks.

Stiles gives him a lopsided grin. "It. Was. _Awesome_."

"Yeah? So we'll be doing this again then?"

"Definitely."

"Good. You have no idea how hot it made me to watch you take it from my dog."

Stiles hums contentedly. "I could find out."

"Hmm?"

Stiles tells him about the fantasy he'd had of Derek being the one getting railed by Prince. He giggles when his words are met with a quiet moan of approval. "You like the idea of that, huh?"

"Hell yeah."

"Not tonight, though. I think I could sleep for week after what Prince did to me."

"Fair enough. I can wait."

For fifteen more minutes, Stiles stays exactly where he is, stuck between his boyfriend and his new mate. When Prince becomes restless and begins tugging to try to free his knot from Stiles' hole, Stiles grunts and lets Derek handle it. The older man prods around his thoroughly used hole, and that's all the warning Stiles gets before Prince yanks his cock out in one go. The pain passes swiftly, and then he falls sideways to lie on the carpet and scrunches up his nose when he feels the husky's come pouring from him.

"Come on, let's get you in the shower," Derek coaxes, taking Stiles' hand. "I'll take care of the carpet in the morning."

One shower later, Stiles falls asleep with Derek wrapped around him and Prince's head on his stomach.

**Author's Note:**

> Well, this PWP was, uh…interesting to write, to say the least. I hadn't written bestiality since [_How Stiles Learned to Love Dog Dick_](https://archiveofourown.org/works/14966981) back in June and figured it was time for it to make a return. I couldn't resist having Stiles rim Prince's doggy asshole too, because apparently I'm one sick motherfucker. I'd like to say a huge thank you to Darksterek for giving me this prompt. I hope it was as gross and depraved as you were hoping it would be. ;)
> 
> Stay tuned for my next PWP, in which Stiles is in a polyamorous relationship with Derek and Peter. Their matching exhibitionist streaks are brought out when he finds a spell that lets them have sex in public without anyone else caring.
> 
> **P.S. Don't forget to subscribe to me to be notified when my future fics go live, which will all be Sterek. And please check out my past fics if you haven't already and are interested.**


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